Compact optical device for augmented reality having ghost image blocking function and wide field of view

ABSTRACT

Disclosed herein is a compact optical device for augmented reality having a ghost image blocking function and a wide field of view. The compact optical device includes: an optical means configured to transmit at least part of real object image light therethrough toward the pupil of an eye of a user; a first reflective means disposed inside the optical means and configured to transfer the augmented reality image light output from an image output unit to a second reflective means; and a second reflective means disposed inside the optical means and to reflect the augmented reality image light, transferred from the first reflective means, and transfer the augmented reality image light to the pupil of the eye of the user, thereby providing an image for augmented reality to the user.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Applications No.10-2019-0138757 filed on Nov. 1, 2019 and No. 10-2019-0174648 filed onDec. 26, 2019, which are hereby incorporated by reference herein in itsentirety.

BACKGROUND 1. Technical Field

The present invention relates generally to an optical device foraugmented reality, and more particularly to a compact optical device foraugmented reality having a ghost image blocking function and a widefield of view, which is capable of significantly reducing the size,thickness, weight, and volume thereof, providing a clearer image foraugmented reality by effectively blocking a ghost image, and providing awide field of view.

2. Description of the Related Art

Augmented Reality (AR) refers to technology that superimposes a virtualimage, generated by a computer or the like, on a real image of the realworld and then provides a resulting image, as is well known.

In order to implement augmented reality, there is required an opticalsystem that allows a virtual image, generated by a device such as acomputer, to be superimposed on an image of the real world and aresulting image to be provided. As such an optical system, there isknown a technology using an optical means such as a prism for reflectingor refracting a virtual image using a head-mounted display (HMD) or aglasses-type device.

However, devices using the conventional optical system have problems inthat it is inconvenient for users to wear them because theconfigurations thereof are complicated and thus the weights and volumesthereof are considerable and in that the manufacturing costs thereof arehigh because the manufacturing processes thereof are also complicated.

Furthermore, the conventional devices have a limitation in that avirtual image becomes out of focus when a user changes focal length whengazing at the real world. To overcome this problem, there have beenproposed technologies such as a technology using a configuration such asa prism capable of adjusting focal length for a virtual image and atechnology for electrically controlling a variable focal lens inresponse to a change in focal length. However, these technologies alsohave a problem in that a user needs to perform a separate operation inorder to adjust focal length or hardware and software such as a separateprocessor for controlling focal length are required.

In order to overcome the problems of the conventional technologies, thepresent applicant has developed an optical device capable ofimplementing augmented reality by projecting a virtual image onto theretina through the pupil using a reflective unit having a size smallerthan that of a human pupil, as described in Korean Patent No. 10-1660519(published on Sep. 29, 2016).

FIG. 1 is a diagram showing the optical device 100 for augmented realitydisclosed in Korean Patent No. 10-1660519.

The optical device 100 for augmented reality, which is shown in FIG. 1 ,includes an optical means 10, a reflective unit 30, an image output unit40, and a frame unit 60.

The optical means 10 is a means for transmitting at least part of realobject image light, which is image light output from a real object,therethrough, and may be, e.g., a lens of eyeglasses. The reflectiveunit 30 is embedded inside the optical means 10. Furthermore, theoptical means 10 also functions to transmit the augmented reality imagelight, reflected by the reflective unit 30, therethrough to the pupil.

The frame unit 60 is a means for fixing and supporting both the imageoutput unit 40 and the optical means 10, and may be, e.g., an eyeglassframe.

The image output unit 40 is a means for outputting augmented realityimage light, which is image light corresponding to an image foraugmented reality. For example, the image output unit 40 may include asmall display device configured to display an image for augmentedreality on a screen and to emit augmented reality image light, and acollimator configured to collimate the image light, emitted from thedisplay device, into parallel light.

The reflective unit 30 reflects image light corresponding to an imagefor augmented reality, output from the image output unit 40, toward thepupil of a user, thereby providing an image for augmented reality to theuser.

The reflective unit 30 shown in FIG. 1 is formed to have a size smallerthan that of the average pupil of people, i.e., 8 mm. By forming thereflective unit 30 to be smaller than the average pupil of people asdescribed above, the depth of field for light entering the pupil throughthe reflective unit 30 may be made almost infinite, i.e., extremelydeep.

The depth of field refers to a range within which an image for augmentedreality is recognized as being in focus. When the depth of fieldincreases, a focal distance for an image for augmented realityincreases. Accordingly, even when a user changes the focal distance forthe real world while gazing at the real world, an image for augmentedreality is always recognized as being in focus regardless of such achange. This may be called as a type of pinhole effect. Thus, a clearvirtual image for an image for augmented reality can be always providedto a user even when user changes the focal distance while gazing at areal object in the real world.

However, this technology has a disadvantages in that the size,thickness, and volume of the device increase because an additionaloptical means such as a collimator for parallel light is required forthe image output unit 40.

In order to overcome this problem, it may be considered that a method ofembedding a reflective unit such as a concave mirror inside the opticalmeans 10 instead of arranging a collimator in the image output unit 40.According to this method, the function of a collimator may be providedby the reflective unit inside the optical means 10 and the size,thickness and, volume of the image output unit 40 can be reduced.

FIG. 2 shows a comparison between a side view of the optical device 100for augmented reality of FIG. 1 in which the image output unit 40 isprovided with a collimator and a side view of an optical device 100-1for augmented reality in which an auxiliary reflective unit 20functioning as a collimator is arranged.

In the optical device 100 for augmented reality of FIG. 1 shown on theleft side of FIG. 2 , the image output unit 40 includes a display device41 and a collimator 42. In contrast, in the optical device 100-1 foraugmented reality shown on the right side of FIG. 2 , an image outputunit 40 includes only a display device 41 without a collimator.

In the optical device 100-1 for augmented reality shown on the rightside of FIG. 2 , a concave mirror-type auxiliary reflective unit 20functioning as a collimator inside an optical means 10 is providedinstead of the collimator 42 in the image output unit 40. The augmentedreality image light output from the image output unit 40 is reflected bythe auxiliary reflective unit 20 and then transmitted to a reflectiveunit 30, and the reflective unit 30 transfers the augmented realityimage light to the pupil.

As described above, the optical device 100-1 for augmented reality shownon the right side of FIG. 2 has the advantage of performing the samefunction as the optical device 100 for augmented reality shown in FIG. 1and also significantly reducing form factors, such as size, volume,thickness, and weight, compared to the optical device 100 for augmentedreality using an external collimator as shown on the left side of FIG. 2because it does not use collimator in the image output unit 40.

However, the optical device 100-1 for augmented reality shown on theright side of FIG. 2 has a problem in that unintended real object imagelight that generates a ghost image may be transmitted to the pupil.

FIG. 3 is a diagram illustrating the principle by which a ghost image isgenerated in the optical device 100-1 for augmented reality.

As shown in FIG. 3 , most of the real object image light, which is imagelight from a real object, is directly transferred to the pupil throughthe optical means 10, however, stray lights may be present which arereflected by the auxiliary reflective unit 20 and transferred to thepupil. The real object image light transmitted to the pupil as straylight forms an image at a location different from that of the realobject image light transferred directly to the pupil through the opticalmeans 10, thereby generating a ghost image.

Therefore, there is a demand for a compact optical device for augmentedreality that is capable of solving the problem of a ghost image that maybe generated in the optical device 100-1 for augmented reality using anembedded collimator such as the auxiliary reflective unit 20 in order toreduce form factors, as shown in FIG. 2 , and is also capable ofexpanding the field of view (FoV), reducing the size, thickness, weight,and volume of the device, and increasing optical efficiency foraugmented reality image light.

SUMMARY

The present invention has been conceived to overcome the above-describedproblems, and an object of the present invention is to provide a compactoptical device for augmented reality, which is capable of significantlyreducing the size, thickness, weight, and volume thereof, effectivelyblocking a ghost image, and providing a wide field of view.

Another object of the present invention is to provide a compact opticaldevice for augmented reality, which is capable of minimizing the leakageof image light of the real world, which may generate a ghost image, tothe pupil of a user, thereby maximizing a see-through property and alsoproviding a clear virtual image, and is also capable of utilizing astructure in which a plurality of reflective units configured totransfer augmented reality image light to the pupil by reflecting ittoward the pupil is arranged, thereby providing a wide field of view andalso improving the optical efficiency at which augmented reality imagelight is transferred to an eye box.

According to an aspect of the present invention, there is provided acompact optical device for augmented reality having a ghost imageblocking function and a wide field of view, the compact optical deviceincluding: an optical means configured to transmit at least part of realobject image light therethrough toward a pupil of an eye of a user; afirst reflective means disposed inside the optical means, and configuredto transfer augmented reality image light which is image lightcorresponding to an image for augmented reality output from an imageoutput unit to a second reflective means; and a second reflective meansdisposed inside the optical means, and configured to reflect theaugmented reality image light transferred from the first reflectivemeans and transfer the augmented reality image light to the pupil of theeye of the user, thereby providing an image for augmented reality to theuser; wherein the optical means has a first surface which the realobject image light enters, and a second surface through which theaugmented reality image light transferred via the second reflectivemeans and the real object image light are output toward the pupil of theeye of the user; wherein the augmented reality image light output fromthe image output unit is transferred to the first reflective meansthrough inner part of the optical means, or is reflected by totalinternal reflection on at least any one of inner surfaces of the opticalmeans and transferred to the first reflective means; wherein areflective surface of the first reflective means which reflects theaugmented reality image light is disposed to face the first surface ofthe optical means which the real object image light enters; wherein thesecond reflective means includes a plurality of reflective unitsdisposed inside the optical means to transfer the augmented realityimage light, transferred from the first reflective means, to the pupilof the user by reflecting the augmented reality image light; and whereinthe plurality of reflective units constituting the second reflectivemeans is arranged inside the optical means such that each of theplurality of reflective units is located closer to the second surface ofthe optical means as a distance from the first reflective means to thereflective unit increases.

The first reflective means may be disposed inside the optical means inopposite to the image output unit with the second reflective meansinterposed therebetween.

The reflective surface of the first reflective means may be formed as acurved surface.

The reflective surface of the first reflective means may be formed to beconcave toward the first surface of the optical means.

The first reflective means may have a length less than 4 mm in awidthwise direction thereof.

The first reflective means may be composed of a half mirror configuredto partially reflect light or a notch filter configured to selectivelytransmit light according to a wavelength of the light.

The first reflective means may be composed of a refractive ordiffractive element.

A surface opposite to the reflective surface of the first reflectivemeans may be coated with a material that absorbs light withoutreflecting light.

The plurality of reflective units constituting the second reflectivemeans may be disposed to have an inclined angle with respect to thesecond surface of the optical means in order to transfer the augmentedreality image light, transferred from the first reflective means, to thepupil by reflecting the augmented reality image light toward the pupil.

Each of the plurality of reflective units may have a size smaller than 4mm.

The size of each of the plurality of reflective units may be a maximumlength between any two points on an edge boundary of the reflectiveunit.

The size of each of the plurality of reflective units may be a maximumlength between any two points on an edge boundary of an orthographicprojection obtained by projecting the reflective unit onto a planeincluding a center of the pupil while being perpendicular to a straightline between the pupil of the user and the reflective unit.

Each of the plurality of reflective units may be disposed such that theaugmented reality image light transmitted from the first reflectivemeans is not blocked by remaining other reflective units.

Sizes of the plurality of reflective parts may be partially differentfrom each other.

An interval between at least some of the plurality of reflective unitsmay be different from an interval between remaining other reflectiveunits.

At least some of the plurality of reflective units may be each composedof a half mirror configured to partially reflect light or a notch filterconfigured to selectively transmit light according to a wavelength ofthe light.

At least some of the plurality of reflective units may be each composedof a refractive or diffractive element.

A surface, being opposite to a surface that reflects the augmentedreality image light, of at least some of the plurality of reflectiveunits may be coated with a material that absorbs light withoutreflecting light.

Surfaces of at least some of the plurality of reflective units may beformed as curved surfaces.

An inclined angle of at least some of the plurality of reflective unitswith respect to the optical means may be formed to be different fromthat of remaining other reflective units.

The second reflective means may include a plurality of reflective means;when the optical means is placed in front of the pupil of the user and adirection that extends forward from the pupil is an x axis, the imageoutput unit may be disposed outside or inside the optical means so thatit is located on a straight line perpendicular to the x axis; and whenany one of line segments passing between the first and second surfacesof the optical means while being parallel to a vertical line from theimage output unit to the x axis along the x axis is a y axis and a linesegment perpendicular to the x axis and the y axis is a z axis, theplurality of second reflective means may be arranged at intervals inparallel with each other along an z axis direction.

Each of a plurality of reflective units constituting each of theplurality of second reflective means may be disposed to be locatedalongside any one of a plurality of reflective units constitutingadjacent second reflective means along a virtual straight line parallelto the z axis.

At least some of a plurality of reflective units constituting each ofthe plurality of second reflective means may be disposed not to belocated alongside any one of a plurality of reflective unitsconstituting adjacent second reflective means on a virtual straight lineparallel to the z axis.

When the optical means is placed in front of the pupil of the user and adirection that extends forward from the pupil is an x axis, the imageoutput unit may be disposed outside or inside the optical means so thatit is located on a straight line perpendicular to the x axis; and whenany one of line segments passing between the first and second surfacesof the optical means while being parallel to a vertical line from theimage output unit to the x axis along the x axis is a y axis and a linesegment perpendicular to the x axis and the y axis is a z axis, theplurality of reflective units may be formed in bar shapes that extendalong virtual straight lines parallel to the z axis.

The first reflective means may extend to become closer to the secondreflective unit in directions from a center of the first reflectivemeans toward both sides of the first reflective means when viewed in thex axis.

According to another aspect of the present invention, there is provideda compact optical device for augmented reality having a ghost imageblocking function and a wide field of view, the compact optical deviceincluding: an optical means configured to transmit at least part of realobject image light therethrough toward a pupil of an eye of a user; afirst reflective means embedded and disposed inside the optical means,and configured to transfer augmented reality image light, which is imagelight corresponding to an image for augmented reality output from animage output unit to a second reflective means; and a second reflectivemeans including a plurality of reflective units embedded and disposedinside the optical means configured to reflect the augmented realityimage light, transferred from the first reflective means, and transferthe augmented reality image light to the pupil of the eye of the user;wherein the optical means has a first surface which the real objectimage light enters, and a second surface through which the augmentedreality image light transferred via the second reflective means and thereal object image light are output toward the pupil of the eye of theuser; wherein the second reflective means comprises: a first reflectiveunit group including a plurality of reflective units that is embeddedand arranged inside the optical means such that each of the plurality ofreflective units has a same distance with respect to the second surfaceof the optical means regardless of a distance from the first reflectivemeans or each of the reflective units is located further away from thesecond surface of the optical means as a distance from the firstreflective means to the reflective unit increases; and a secondreflective unit group including a plurality of reflective units that isembedded and arranged inside the optical means so that each of thereflective units is located closer to the second surface of the opticalmeans as a distance from the first reflective means to the reflectiveunit increases; and wherein a distance between the second reflectiveunit group and the first reflective means is shorter than a distancebetween the first reflective unit group and the first reflective means.

The augmented reality image light output from the image output unit maybe transferred to the first reflective means through inner part of theoptical means, or is reflected by total internal reflection on at leastany one of inner surfaces of the optical means at least once andtransferred to the first reflective means.

A reflective surface of the first reflective means which reflects theaugmented reality image light may be disposed to face the first surfaceof the optical means which the real object image light enters.

A reflective surface of the first reflective means may be formed as acurved surface.

The reflective surface of the first reflective means may be formed to beconcave toward the first surface of the optical means.

The first reflective means may have a length less than 4 mm in awidthwise direction thereof.

The plurality of reflective units constituting the second reflectivemeans may be disposed to have an inclined angle with respect to thesecond surface of the optical means in order to transfer the augmentedreality image light, transferred from the first reflective means, to thepupil by reflecting the augmented reality image light toward the pupil.

Each of the plurality of reflective units may have a size smaller than 4mm.

At least some of the plurality of reflective units may be each composedof at least one of a half mirror, a refractive element, and adiffractive element.

A surface, being opposite to a surface that reflects the augmentedreality image light, of at least some of the plurality of reflectiveunits may be coated with a material that absorbs light withoutreflecting light.

The second reflective means may include a plurality of reflective means;when the optical means is placed in front of the pupil of the user and adirection that extends forward from the pupil is an x axis, the imageoutput unit may be disposed outside or inside the optical means so thatit is located on a straight line perpendicular to the x axis; and whenany one of line segments passing between the first and second surfacesof the optical means while being parallel to a vertical line from theimage output unit to the x axis along the x axis is a y axis and a linesegment perpendicular to the x axis and the y axis is a z axis, theplurality of second reflective means may be arranged at intervals inparallel with each other along an z axis direction.

Each of the second reflective means may be arranged such that each of aplurality of reflective units constituting each of the plurality ofsecond reflective means is disposed to be located alongside any one of aplurality of reflective units constituting adjacent second reflectivemeans along a virtual straight line parallel to the z axis.

At least some of a plurality of reflective units constituting each ofthe plurality of second reflective means may be disposed not to belocated alongside a plurality of reflective units constituting adjacentsecond reflective means on a virtual straight line parallel to the zaxis.

When the optical means is placed in front of the pupil of the user and adirection that extends forward from the pupil is an x axis, the imageoutput unit may be disposed outside or inside the optical means so thatit is located on a straight line perpendicular to the x axis; and whenany one of line segments passing between the first and second surfacesof the optical means while being parallel to a vertical line from theimage output unit to the x axis along the x axis is a y axis and a linesegment perpendicular to the x axis and the y axis is a z axis, theplurality of reflective units may be formed in bar shapes that extendalong virtual straight lines parallel to the z axis.

The first reflective means may extend to become closer to the secondreflective unit in directions from a center of the first reflectivemeans toward both sides of the first reflective means when is viewed inthe x axis.

A third surface through which the augmented reality image light outputfrom the image output unit enters the optical means may be formed as acurved surface having refractive power.

An auxiliary optical means may be disposed between the image output unitand the third surface.

The second reflective means may include a plurality of reflective means;and when the optical device is placed in front of the pupil of the user,a direction that extends forward from the pupil is an x axis, any one ofline segments passing between the first and second surfaces of theoptical means while being parallel to a vertical line from the imageoutput unit to the x axis along the x axis is a y axis, and a linesegment perpendicular to the x axis and the y axis is a z axis, theremay be at least one of the second reflective means that is disposed suchthat distances between the second reflecting means and the secondsurface of the optical means are not the same as each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the presentinvention will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a diagram showing the optical device for augmented realitydisclosed in Korean Patent No. 10-1660519;

FIG. 2 shows a comparison between a side view of the optical device foraugmented reality of FIG. 1 in which an image output unit is providedwith a collimator and a side view of an optical device for augmentedreality in which an auxiliary reflective unit functioning as acollimator is disposed;

FIG. 3 is a diagram illustrating the principle by which a ghost image isgenerated in the latter optical device for augmented reality;

FIGS. 4 and 5 are diagrams showing the configuration of a compactoptical device for augmented reality having a ghost image blockingfunction and a wide field of view according to a first embodiment of thepresent invention, wherein FIG. 4 is a side view of this optical devicefor augmented reality and FIG. 5 is a perspective view of this opticaldevice for augmented reality;

FIG. 6 is a diagram illustrating the principle by which a firstreflective means blocks a ghost image;

FIGS. 7 and 8 are diagrams showing the configuration of an opticaldevice for augmented reality according to a modification of the firstembodiment of the present invention, wherein FIG. 7 is a perspectiveview of this optical device for augmented reality, and FIG. 8 is a frontview of this optical device for augmented reality;

FIGS. 9 and 10 are diagrams showing the configuration of an opticaldevice for augmented reality according to another modification of thefirst embodiment of the present invention, wherein FIG. 9 is aperspective view of this optical device for augmented reality and FIG.10 is a front view of this optical device for augmented reality;

FIGS. 11 and 12 are diagrams showing the configuration of an opticaldevice for augmented reality according to still another modification ofthe first embodiment of the present invention, wherein FIG. 11 is aperspective view of this optical device for augmented reality and FIG.12 is a front view of this optical device for augmented reality;

FIGS. 13 and 14 are side and perspective views showing an optical devicefor augmented reality according to a second embodiment of the presentinvention, respectively;

FIGS. 15 to 20 are diagrams illustrating a total internal reflectionstructure for total internal reflection on an inner surface of anoptical means;

FIGS. 21 and 22 are diagrams showing the configuration of an opticaldevice for augmented reality according to a modification of the secondembodiment of the present invention, wherein FIG. 21 is a perspectiveview of this optical device for augmented reality and FIG. 22 is a frontview of this optical device for augmented reality;

FIGS. 23 and 24 are diagrams showing the configuration of an opticaldevice for augmented reality according to another modification of thesecond embodiment of the present invention, wherein FIG. 23 is aperspective view of this optical device for augmented reality and FIG.24 is a front view of this optical device for augmented reality;

FIGS. 25 and 26 are diagrams showing the configuration of an opticaldevice for augmented reality according to still another modification ofthe second embodiment of the present invention, wherein FIG. 25 is aperspective view of this optical device for augmented reality and FIG.26 is a front view of this optical device for augmented reality;

FIG. 27 is a side view showing an optical device for augmented realityaccording to a third embodiment of the present invention;

FIG. 28 is a side view showing an optical device for augmented realityaccording to a modification of the third embodiment of the presentinvention; and

FIGS. 29 to 31 are diagrams showing an optical device for augmentedreality according to a fourth embodiment of the present invention,wherein FIG. 29 is a front view showing this optical device foraugmented reality when viewed from the pupil, FIG. 30 is a side viewshowing this optical device for augmented reality when viewed toward aplane perpendicular to an z axis, and FIG. 31 is a plan view showingthis optical device for augmented reality when viewed toward a planeperpendicular to an y axis.

DETAILED DESCRIPTION

Embodiments of the present invention will be described in detail belowwith reference to the accompanying drawings.

First Embodiment

First, a first embodiment of the present invention and modificationsthereof will be described with reference to FIGS. 4 to 12 .

FIGS. 4 and 5 are diagrams showing the configuration of a compactoptical device 200 for augmented reality having a ghost image blockingfunction and a wide field of view (hereinafter simply referred to as the“optical device 200 for augmented reality”) according to the firstembodiment of the present invention, wherein FIG. 4 is a side view ofthe optical device 200 for augmented reality and FIG. 5 is a perspectiveview of the optical device 200 for augmented reality.

Referring to FIGS. 4 and 5 , the optical device 200 for augmentedreality according to the present embodiment includes an optical means10, a first reflective means 20, and a second reflective means 30.

The optical means 10 is a means for transmitting at least part of realobject image light, which is the image light output from a real object,therethrough toward the pupil 50 of an eye of a user.

Here, the fact that at least part of real object image light istransmitted toward the pupil 50 means that the light transmittance ofthe real object image light does not necessarily need to be 100%.

The optical means 10 has first surface 11 and second surfaces 12 thatare opposite to each other. The first surface 11 is a surface which thereal object image light enters, and the second surface 12 is a surfacethrough which the augmented reality image light reflected by the secondreflective means 30 and the real object image light transmitted throughthe first surface 11 are output toward the pupil 50 of the eye of theuser.

In FIGS. 4 and 5 , a total internal reflection (TIR) structure is shownin which the augmented reality image light output from the image outputunit 40 is reflected by total internal reflection on the first surface11 of the optical means 10 and transmitted to the first reflective means20, however, the augmented reality image light output from the imageoutput unit 40 may be directly transmitted to the first reflective means20 through the inner part of the optical means 10 without total internalreflection.

When the total internal reflection structure is not used, i.e., when theaugmented reality image light output from the image output unit 40 isdirectly transmitted to the first reflective means 20, the image outputunit 40 may be disposed at an appropriate location inside or outside theoptical means 10 in consideration of the angle of the first reflectivemeans 20.

When the total internal reflection structure is used, the augmentedreality image light output from the image output unit 40 is reflected bytotal internal reflection on the first surface 11 of the optical means10 and transmitted to the first reflective means 20. Then, the augmentedreality image light reflected by the first reflective means 20 isreflected again by the second reflective means 30 and output to thepupil 50 through the second surface 12 of the optical means 10, as shownin FIGS. 4 and 5 .

In this case, the second reflective means 30 includes a plurality ofreflective units 31 to 35. In the present specification, the pluralityof reflective units 31 to 35 is collectively referred to as the secondreflective means 30. The detailed configuration of the second reflectivemeans 30 will be described later.

The image output unit 40 is a means for outputting augmented realityimage light, which is image light corresponding to an image foraugmented reality. The image output unit 40 outputs augmented realityimage light to the first reflective means 20 or toward the first surface11 of the optical means 10, as described above. The image output unit 40may be, for example, a small-sized display device such as a liquidcrystal display (LCD). Since the image output unit 40 itself is not adirect target of the present invention and is known in prior art, adetailed description thereof will be omitted below. However, the imageoutput unit 40 according to the present embodiment does not include acomponent such as a collimator described in the description of therelated art.

Meanwhile, the image for augmented reality refers to a virtual imagetransmitted to the pupil 50 of the user through the image output unit40, the optical means 10, the first reflective means 20, and the secondreflective means 30. The image for augmented reality may be a stillimage or moving image in the form of an image.

The image for augmented reality is transferred to the pupil 50 of theuser by the image output unit 40, the optical means 10, the firstreflective means 20, and the second reflective means 30, therebyproviding a virtual image to the user. At the same time, the real objectimage light output from a real object present in the real world isprovided to the user through the optical means 10. Accordingly, anaugmented reality service can be provided to the user.

The first reflective means 20 is a means for transmitting the augmentedreality image light output from the image output unit 40 to the secondreflective means 30 and is disposed inside the optical means 10.

As described above, the image output unit 40 outputs augmented realityimage light toward the first reflective means 20 or the first surface 11of the optical means 10. When the total internal reflection structure isused, the augmented reality image light reflected by total internalreflection on the first surface 11 of the optical means 10 istransferred to the first reflective means 20, and the augmented realityimage light reflected by the first reflective means 20 is transferred tothe second reflective means 30. Then, the augmented reality image lightis reflected again by the second reflective means 30 and directed towardthe pupil 50.

In the case where the total internal reflection structure is not used,the augmented reality image light output from the image output unit 40is directly transferred to the first reflective means 20 and theaugmented reality image light reflected by the first reflective means 20is transferred to the second reflective means 30. The augmented realityimage light transferred to the second reflective means 30 is reflectedagain by the second reflective means 30 and directed to the pupil 50.

In the case where the total internal reflection structure is used, thefirst reflective means 20 is disposed inside the optical means 10 inopposite to the image output unit 40 with the second reflective means 30interposed therebetween.

Furthermore, the first reflective means 20 is embedded in the opticalmeans 10 between the first surface 11 and second surfaces 12 so that itcan reflect augmented reality image light toward the second reflectivemeans 30.

In other words, the first reflective means 20 is embedded in the opticalmeans 10 between the first surface 11 and second surfaces 12 so that itcan reflect and transfer the augmented reality image light output fromthe image output unit 40 or the augmented reality image lighttransferred by being reflected by total internal reflection on the firstsurface 11 of the optical means 10 to the second reflective means 30.

In this case, the statement that the first reflective means 20 isembedded in the optical means 10 means that the first reflective means20 is disposed in the internal space of the optical means 10 while beingspaced apart from the first and second surfaces 11 and 12 of the opticalmeans 10 by predetermined distances.

Furthermore, the first reflective means 20 is disposed inside theoptical means 10 so that the reflective surface 21 of the firstreflective means 20 to reflect augmented reality image light faces thefirst surface 11 of the optical means 10 which real object image lightenters. According to this configuration, the first reflective means 20can filter out the stray light which is a part of the real object imagelight output from a real object and generates a ghost image in order toprevent the stray light from being transferred to the pupil 50 throughthe second reflective means 30 or the second surface 12 of the opticalmeans 10 while transferring augmented reality image light to the secondreflective means 30.

Meanwhile, the reflective surface 21 of the first reflective means 20may be famed as a curved surface. For example, the reflective surface 21of the first reflective means 20 may be a concave mirror formed to beconcave toward the direction of the first surface 11 of the opticalmeans 10, as shown in FIGS. 4 and 5 . By this, the first reflectivemeans 20 may function as a collimator for collimating the augmentedreality image light output from the image output unit 40. Accordingly,it is not necessary to use a collimator in the image output unit 40.

FIG. 6 is a diagram illustrating the principle by which the firstreflective means 20 prevents a ghost image.

The second reflective means 30 is omitted from FIG. 6 for ease ofdescription.

As shown in FIG. 6 , the real object image light (stray light) that isemitted from a real object and generates a ghost image enters the firstreflective means 20. As described above, the first reflective means 20is disposed to face the first surface 11 of the optical means 10 whichreal object image light enters. Accordingly, it can be seen that thereal object image light (stray light) to generate a ghost image isreflected on the reflective surface 21 of the first reflective means 20and is directed to the second surface 12 of the optical means 10. Then,it is reflected by total internal reflection on the second surface 12 ofthe optical means 10 and is directed toward in the direction of theimage output unit 40. Accordingly, it can be seen that the real objectimage light (stray light) emitted from a real object which may generatea ghost image, is dissipated inside the optical means 10 and does notleak toward the pupil 50.

However, this principle is the basic exemplary illustration forpreventing the real object image light (stray light) reflected by thefirst reflective means 20 from leaking out of the optical means 10. Inpractice, for minimizing external light (stray light) which is reflectedby the first reflective means 20 and is directed to the pupil 50, thelocation and direction of the first reflective means 20 need to beappropriately adjusted in consideration of the shape of the opticalmeans 10, refractive index of the optical means 10, the locations of theeye and the first reflective means 20, the size of the pupil, and eyerelief.

Meanwhile, as will be described later, the size of the second reflectivemeans 30 is formed to be smaller than 8 mm, which is the size of theaverage pupil of people, more preferably 4 mm. When this point is takeninto account, the length of the first reflecting means 20 in thewidthwise direction thereof is formed to be smaller than 8 mm, morepreferably 4 mm, so as to correspond to the size of the secondreflective means 30.

In this case, the length of the first reflective means 20 in thewidthwise direction refers to the length in the direction that extendsbetween the first and second surfaces 11 and 12 of the optical means 10in FIGS. 4 and 5 .

Alternatively, the length of the first reflective means 20 in thewidthwise direction may be the length between both ends of the firstreflective means 20 when the first reflective means 20 is viewed towarda surface perpendicular to the z-axis direction from the outside in FIG.5 .

Furthermore, it is preferable that the first reflective means 20 have asignificantly small thickness when viewed from the pupil 50 in order toallow the user to rarely recognize the first reflective unit 20 throughthe pupil 50.

Furthermore, the first reflective means 20 may be formed as a halfmirror that partially reflects light.

Furthermore, the first reflective means 20 may be composed of arefractive element or diffractive element other than the reflectivemeans.

Furthermore, the first reflective means 20 may be composed of an opticalelement such as a notch filter that selectively transmits lightaccording to its wavelength.

Furthermore, the surface opposite to the reflective surface 21 of thefirst reflective means 20 that reflects augmented reality image lightmay be coated with a material that absorbs light without reflecting it.

Referring again to FIGS. 4 and 5 , the second reflective means 30 willbe described below.

The second reflective means 30 is disposed inside the optical means 10,and is a means for reflecting the augmented reality image lighttransferred from the first reflective means 20 and transferringaugmented reality image light to the pupil 50 of the eye of the user,thereby providing an image for augmented reality to the user. The secondreflective means 30 includes the plurality of reflective units 31 to 35.

The plurality of reflective units 31 to 35 is disposed to be embedded inthe optical means 10 in order to transfer the augmented reality imagelight, transferred from the first reflective means 20, to the pupil 50of the user by reflecting it. In other words, the plurality ofreflective units 31 to 35 is disposed in the internal space of theoptical means 10 with being spaced apart from the first and secondsurfaces 11 and 12 of the optical means 10 by predetermined distances.

As described above, the augmented reality image light output from theimage output unit 40 is transmitted to the second reflective means 30through the first reflective means 20. Accordingly, each of theplurality of reflective units 31 to 35 constituting the secondreflective means 30 is disposed to have an appropriate inclined anglewith respect to the second surface 12 of the optical means 10 by takinginto account the locations of the first reflective means 20 and thepupil 50.

Each of the plurality of reflective units 31 to 35 is formed to besmaller than the size of the average pupil of people, i.e., 8 mm, morepreferably 4 mm, in order to obtain a pinhole effect by increasing thedepth of field, as described in the description of the related art.

In other words, by forming the plurality of reflective units 31 to 35 tobe smaller than the size of the average pupil of people, i.e., 8 mm, thedepth of field for the light entering the pupil through the reflectiveunit 30 may be made almost infinite, i.e., extremely deep. Accordingly,there may be achieved a pinhole effect that allows an image foraugmented reality to be always recognized as being in focus regardlessof a change in the focal distance even when a user changes the focaldistance for the real world while gazing at the real world.

In this case, the size of each of the plurality of reflective units 31to 35 is defined as the maximum length between any two points on theedge boundary of each of the reflective units 31 to 35.

Furthermore, the size of each of the plurality of reflective units 31 to35 may be the maximum length between any two points on the edge boundaryof an orthographic projection obtained by projecting each of theplurality of reflective units 31 to 35 onto a plane that isperpendicular to a straight line between the pupil 50 and the reflectingunits 31 to 35 and includes the center of the pupil 50.

Meanwhile, in the present invention, when the size of the reflectiveunits 31 to 35 is excessively small, a diffraction phenomenon in thereflective units 31 to 35 may increase, and thus the size of each of thereflective units 31 to 35 is preferably larger than, e.g., 0.3 mm.

Furthermore, the shape of each of the reflective units 31 to 35 ispreferably circular. In this case, the shape of the reflective units 31to 35 may be formed to appear circular when the reflective units 31 to35 are viewed from the pupil 50.

Also, each of the plurality of reflective units 31 to 35 is disposedsuch that the augmented reality image light transmitted from the firstreflective means 20 is not blocked by the other reflective units 31 to35. To this end, in the embodiments of FIGS. 4 and 5 , the plurality ofreflective units 31 to 35 may be arranged inside the optical means 10such that, as the distance from the first reflective means 20 to each ofthe reflective units 31 to 35 increases, the reflective units 31, 32,33, 34 or 35 are located closer to the inner surface of the opticalmeans 10, i.e., the second surface 12 of the optical means 10, throughwhich augmented reality image light is output toward the pupil 50.

As shown in FIGS. 4 and 5 , when the optical means 10 is placed in frontof the pupil 50 of the user and the direction that extends forward fromthe pupil 50 is an x axis, the image output unit 40 is disposed insideor outside the optical means 10 so that it is located on a straight lineperpendicular to the x axis.

In this case, when any one of the line segments passing between thefirst and second surfaces 11 and 12 of the optical means 10 while beingparallel to a vertical line from the image output unit 40 to the x axisalong the x axis is a y axis and a line segment perpendicular to the xaxis and the y axis is a z axis, the plurality of reflective units 31 to35 are arranged inside the optical means 10 such that when the opticalmeans 10 is viewed from the outside toward a plane perpendicular to thez axis, each of the plurality of reflective units 31 to 35 is locatedcloser to the second surface 12 of the optical means 10 as the distancefrom the first reflective means 20 to the reflective unit 31, 32, 33, 34or 35 increases, as shown in FIG. 4 .

It can be seen that, according to this configuration, the augmentedreality image light output from any one point of the image output unit40 is reflected by total internal reflection on the first surface 11 ofthe optical means 10 and transferred to the first reflective means 20functioning as a collimator, the augmented reality image light reflectedby the first reflective means 20 is transferred to the plurality ofreflective units 31 to 35. Then, the augmented reality image lightreflected by the plurality of reflective units 31 to 35 is transferredto a point of the retina of the user through the pupil 50, therebyforming an image.

In this case, the sizes of the plurality of reflective units 31 to 35are not necessarily the same, and may be partially different from eachother.

Furthermore, although it is preferable that the plurality of reflectiveunits 31 to 35 be disposed at the same intervals, the interval betweenat least some of the reflective units 31 to 35 may be different from theinterval between the other reflective units 31 to 35.

Furthermore, at least some of the plurality of reflective units 31 to 35may be configured as half mirrors that partially reflect light.

Furthermore, at least some of the plurality of reflective units 31 to 35may be composed of refractive elements or diffractive elements otherthan the reflective means.

Furthermore, at least some of the plurality of reflective units 31 to 35may be composed of optical elements such as notch filters thatselectively transmit light according to the wavelength.

Furthermore, the surface, being opposite to the surface that reflectsaugmented reality image light, of at least some of the plurality ofreflective units 31 to 35 may be coated with a material that absorbslight without reflecting light.

Furthermore, the surfaces of at least some of the plurality ofreflective units 31 to 35 may be formed as curved surfaces. In thiscase, the curved surfaces may be concave surfaces or convex surfaces.

Furthermore, the inclined angle of at least some of the plurality ofreflective units 31 to 35 with respect to the optical means 10 may beformed to be different from the inclined angle of the other reflectiveunits 31 to 35.

FIGS. 7 and 8 are diagrams showing the configuration of an opticaldevice 300 for augmented reality according to a modification of thefirst embodiment of the present invention, wherein FIG. 7 is aperspective view of the optical device 300 for augmented reality, andFIG. 8 is a front view of the optical device 300 for augmented reality.

The optical device 300 for augmented reality shown in FIGS. 7 and 8 hasthe same basic configuration as the optical device 200 for augmentedreality shown in FIGS. 4 to 6 , however, it is characterized in that aplurality of second reflecting means 301 to 304 is provided, whereineach of the second reflecting means 301 to 304 includes a plurality ofreflective units 31 to 35.

In this case, the plurality of second reflective means 301 to 304 isarranged as below:

When an optical means 10 is placed in front of the pupil 50 of a userand the direction that extends forward from the pupil 50 is an x axis,an image output unit 40 is disposed inside or outside the optical means10 so that it is located on a straight line perpendicular to the x axis,as described above. Also, when any one of the line segments passingbetween the first and second surfaces 11 and 12 of the optical means 10while being parallel to a vertical line along the x axis from the imageoutput unit 40 to the x axis is a y axis and a line segmentperpendicular to the x axis and the y axis is a z axis, the plurality ofsecond reflective means 301 to 304 is arranged at intervals in parallelwith each other along the z axis direction.

Each of a plurality of reflective units 31 to 35 constituting each ofthe plurality of second reflective means 301 to 304 may be disposedalongside any one of a plurality of reflective units 31 to 35constituting adjacent second reflective means 301 to 304 (i.e., secondreflective means 301 to 304 provided on both sides) along a virtualstraight line parallel to the z axis.

In this case, when the optical means 10 is viewed toward a planeperpendicular to the z axis, the plurality of second reflecting means301 to 304 appears the same as shown in FIG. 4 .

According to the embodiments shown in FIGS. 7 and 8 , there is providedthe advantage of expanding the field of view and eye box in the z-axisdirection while having the same effect as the optical device 200 foraugmented reality shown in FIGS. 4 to 6 .

FIGS. 9 and 10 are diagrams showing the configuration of an opticaldevice 400 for augmented reality according to another modification ofthe first embodiment of the present invention, wherein FIG. 9 is aperspective view of the optical device 400 for augmented reality andFIG. 10 is a front view of the optical device 400 for augmented reality.

The optical device 400 for augmented reality according to the embodimentof FIGS. 9 and 10 is basically the same as the optical device 300 foraugmented reality described in conjunction with FIGS. 7 and 8 , however,it is characterized in that at least some of a plurality of reflectiveunits 31 to 35 constituting each of a plurality of second reflectivemeans 301 to 304 are arranged not to be located alongside any one of aplurality of reflective units 31 to 35 constituting adjacent secondreflective means 301 to 304 on a virtual straight line parallel to the zaxis.

Referring to FIGS. 9 and 10 , when the reflective units 31 to 35 of thefirst reflective means 301 and the reflective units 31 to 35 of thesecond reflective means 302, which are adjacent to each other from theright direction of the z axis, are compared with each other in sequencefrom an upper side (a side adjacent to an image output unit 40) in they-axis direction, it can be seen that each of the reflective units 31 to35 of the first reflective means 301 is arranged not to be locatedalongside any one of the reflective units 31 to 35 of the secondreflective means 302 on a virtual straight line parallel to the z axis.

In other words, it can be seen that the reflective units 31 to 35 of thefirst reflective means 301 and the reflective units 31 to 35 of thesecond reflective means 302 are not arranged alongside each other andare not aligned with each other along a virtual straight line parallelto the z axis when is viewed from the outside toward a planeperpendicular to the z-axis direction.

FIGS. 11 and 12 show the configuration of an optical device 500 foraugmented reality according to still another modification of the firstembodiment of the present invention, wherein FIG. 11 is a perspectiveview of the optical device 500 for augmented reality and FIG. 12 is afront view of the optical device 500 for augmented reality.

Although the optical device 500 for augmented reality shown in FIGS. 11and 12 is basically the same as the optical device 200 for augmentedreality described in conjunction with FIGS. 4 and 5 , it ischaracterized in that a plurality of reflective units 31 to 35 is formedin bar shapes that extend along virtual straight lines parallel to a zaxis.

In other words, as described above, when an optical means 10 is placedin front of the pupil 50 of a user and the direction that extendsforward from the pupil 50 is an x axis, an image output unit 40 isdisposed outside or inside the optical means 10 so that it can belocated on a straight line perpendicular to the x axis. Also, when anyone of the line segments passing between the first and second surfaces11 and 12 of the optical means 10 while being parallel to a verticalline from the image output unit 40 to the x axis along the x axis is a yaxis and a line segment perpendicular to the x axis and the y axis is az axis, the plurality of reflective units 31 to 35 is formed in barshapes that extend along virtual straight lines parallel to the z axis.

Even in this embodiment, when the optical means 10 is viewed toward aplane perpendicular to the z axis, the plurality of reflective units 31to 35 appears the same as shown in FIG. 4 .

Meanwhile, in the embodiments of FIGS. 4 to 12 , the first reflectivemeans 20 extends to become closer to the second reflective means 301 to304 in the directions from the center of the first reflective means 20toward both sides of the first reflective means 20 when the opticalmeans 10 is viewed toward a plane perpendicular to the x axis. Thus, thefirst reflective means 20 is formed in the shape of a moderate“U”-shaped bar as a whole.

In this case, the overall length of the first reflective means 20 in thez-axis direction may correspond to or be slightly longer than the wholelength of the plurality of second reflective means 301 to 304 in thez-axis direction.

Even in this case, the length of the first reflecting means 20 in thewidthwise direction thereof may be formed to be less than 4 mm, and thereflective surface 21 to reflect augmented reality image light may beformed be concave toward the first surface 11 of the optical means 10,which is a direction in which real object image light enters.

Second Embodiment

A second embodiment of the present invention and modifications thereofwill be described with reference to FIGS. 13 to 31 .

FIGS. 13 and 14 are side and perspective views showing an optical device600 for augmented reality according to the second embodiment of thepresent invention, respectively.

Referring to FIGS. 13 and 14 , the optical device 600 for augmentedreality according to the present embodiment includes an optical means10, a first reflective means 20, and a second reflective means 30.

The optical device 600 for augmented reality according to the presentembodiment is basically the same as the optical device 200 for augmentedreality described in conjunction with FIGS. 4 and 5 , however, itdiffers from the optical device 200 for augmented reality in arrangementof a plurality of reflective units 31 to 35 constituting a secondreflective means 30.

The second reflective means 30 of the optical device 600 for augmentedreality shown in FIGS. 13 and 14 includes a first reflective unit group30A including a plurality of reflective units 31 and 32 a secondreflective unit group 30B including a plurality of reflective units 33to 35. Also, the first and second reflective unit groups 30A and 30B arearranged such that the distance between the second reflective unit group30B and the first reflective means 20 is shorter than the distancebetween the first reflective unit group 30A and the first reflectivemeans 20.

Furthermore, the plurality of reflective units 31 and 32 constitutingthe first reflective unit group 30A is embedded and arranged inside theoptical means 10 so that each of the reflective units 31 and 32 islocated further away from the second surface 12 of the optical means 10as the distance from the first reflective means 20 to the reflectiveunit 31 or 32 increases, as shown in FIG. 13 . However, this isillustrative, and the plurality of reflective units 31 and 32 may havethe same distance with respect to the second surface 12 of the opticalmeans 10 regardless of the distance from the first reflective means 20.

Furthermore, the plurality of reflective units 33 to 35 constituting thesecond reflective unit group 30B are embedded and arranged inside theoptical means 10 so that each of the reflective units 33 to 35 islocated closer to the second surface 12 of the optical means 10 as thedistance from the first reflective means 20 to the reflective unit 33,34 or 35 increases.

Referring to FIGS. 13 and 14 , when the optical means 10 is placed infront of the pupil 50 of a user and the direction that extends forwardfrom the pupil 50 is an x axis, an image output unit 40 is disposedoutside or inside the optical means 10 so that it is located on astraight line perpendicular to the x axis.

Furthermore, when any one of the line segments passing between the firstand second surfaces 11 and 12 of the optical means 10 while beingparallel to a vertical line from the image output unit 40 to the x axisalong the x axis is a y axis and a line segment perpendicular to the xaxis and the y axis is a z axis, the plurality of reflective units 31 to35 appears to be arranged in a moderate “C”-shaped form when the opticalmeans 10 is viewed toward a plane perpendicular to the z axis, as shownin FIG. 13 .

Although only a structure in which as the distance from the firstreflective means 20 to each of the plurality of reflective units 31 and32 constituting the first reflective unit group 30A increases, thereflective unit 31 or 32 is located further away from the second surface12 of the optical means 10 is illustrated in FIGS. 13 and 14 , theplurality of reflective units 31 and 32 constituting the firstreflective unit group 30A may be arranged to have the same distance withrespect to the second surface 12 of the optical means 10 regardless ofthe distance from the first reflective means 20.

In this case, there may be cases where at least any one of the first andsecond surfaces 11 and 12 of the optical means 10 may be formed as acurved surface or may be formed to have an inclined angle with respectto a plane perpendicular to the straight line that extends forward fromthe center of the pupil 50, i.e., the x axis, rather than being parallelto the plane.

Accordingly, the statement that, as the distance from the firstreflective means 20 to each of the plurality of reflective units 33 to35 increases, the reflective unit 31 or 32 is located further away fromthe second surface 12 of the optical means 10 means that, as thedistance from the first reflective means 20 to each of the reflectiveunits increases, the reflective unit is located further away from avertical plane present between the second surface 12 and the pupil 50,which is a plane perpendicular to a straight line in the direction thatextends forward from the pupil 50.

In the same manner, the statement that, as the distance from the firstreflective means 20 to each of the reflective units increases, thereflective unit is located closer to the second surface 12 of theoptical means 10 means that the distance from the first reflective means20 to each of the reflective units increases, the reflective unit islocated closer to a vertical plane present between the second surface 12and the pupil 50, which is a plane perpendicular to a straight line inthe direction that extends forward from the pupil 50.

According to this configuration, as shown in FIG. 13 , it can be seenthat the augmented reality image light output from one point of theimage output unit 40 is reflected by the first reflective means 20functioning as a collimator and transferred to each of the plurality ofreflective units 31 to 35 and the augmented reality image lightreflected by each of the reflective units 31 to 35 is transferred to onepoint of the retina of the user through the pupil 50, thereby forming animage.

In FIGS. 13 and 14 , the first reflective unit group 30A is composed ofthe adjacent reflective units 31 and 32, however, this is illustrative.Alternatively, the first reflective unit group 30A may includereflective units that are not adjacent to each other. This also appliesto the second reflective unit group 30B.

Furthermore, the first reflective unit group 30A and the secondreflective unit group 30B may include a plurality of groups.

Furthermore, each of the plurality of reflective units 31 to 35constituting the second reflective means 30 is not necessarily includedin any one of the first and second reflective unit groups 30A and 30B.Furthermore, only some of the plurality of reflective units 31 to 35constituting the second reflective means 30 may constitute the first andsecond reflective unit groups 30A and 30B.

Meanwhile, since other structural features of the second reflectivemeans 30, the optical means 10, and the first reflective means 20 in theembodiment shown in FIGS. 13 and 14 are the same as those of the firstembodiment described with reference to FIGS. 4 to 12 , detaileddescriptions thereof will be omitted below.

Meanwhile, in the second embodiment, although the augmented realityimage light output from the image output unit 40 has been described asbeing reflected by total internal reflection on the first surface 11 ofthe optical means 10 and then transferred to the first reflective means20, a configuration without total internal reflection or with two ormore total internal reflections may be adopted.

FIGS. 15 to 20 are diagrams illustrating total internal reflection on aninner surface of the optical means 10.

FIG. 15 shows a case where total internal reflection is not performed onthe inner surface of an optical means 10. As shown in FIG. 15 , it canbe seen that the augmented reality image light output from an imageoutput unit 40 is directly transmitted to a first reflecting means 20without total internal reflection through the interior of the opticalmeans 10 and the augmented reality image light reflected by the firstreflective means 20 is reflected by a second reflective means 30, i.e.,a plurality of reflective units 31 to 35, and transmitted to the pupil50.

FIG. 16 shows a case where total internal reflection is performed twiceon the inner surface of an optical means 10. As shown in this drawing,it can be seen that the augmented reality image light output from animage output unit 40 is reflected by total internal reflection on thefirst surface 11 of the optical means 10 and transmitted to a firstreflective means 20. Then, the augmented reality image light reflectedby the first reflective means 20 is emitted toward the first surface 11of the optical means 10 and is reflected again by total internalreflection on the first surface 11. After then, the augmented realityimage light is transferred to a second reflective means 30 and isreflected by the second reflective means 30, and transmitted to thepupil 50.

It can be seen that the structure shown in FIG. 16 is substantially thesame as a structure obtained by, when the optical means 10 shown in FIG.15 is viewed toward a plane perpendicular to the z axis, bisecting theoptical means 10 shown in FIG. 15 along the x axis, setting a bisectingline to a first surface 11, and symmetrically transforming the firstreflective means 20 shown in FIG. 15 with respect to the bisecting line.

FIG. 17 shows another case where total internal reflection is notperformed on the inner surface of an optical means 10. As shown in thisdrawing, it can be seen that the augmented reality image light outputfrom an image output unit 40 is directly transferred to a firstreflective means 20 without total internal reflection through theinterior of the optical means 10 and the augmented reality image lightreflected by the first reflective means 20 is reflected by a secondreflective means 30, i.e., a plurality of reflective units 31 to 35, andtransferred to the pupil 50.

Although the example shown in FIG. 17 is similar to the example shown inFIG. 15 , there are differences in the location of the image output unit40 and the location and angle of the first reflective means 20.

FIG. 18 shows another case where total internal reflection is performedonce on the inner surface of an optical means 10. As shown in thisdrawing, it can be seen that the augmented reality image light outputfrom an image output unit 40 is transferred to a first reflective means20 and the augmented reality image light reflected by the firstreflective means 20 is emitted to the first surface 11 of the opticalmeans 10, reflected by total internal reflection on the first surface11, transferred to the second reflective means 30, reflected by thesecond reflective means 30, and transferred to the pupil 50.

It can be seen that the structure shown in FIG. 18 is substantially thesame as a structure obtained by, when the optical means 10 shown in FIG.17 is viewed toward a plane perpendicular to the z-axis direction,bisecting the optical means 10 shown in FIG. 17 along the x axis,setting a bisecting line to a first surface 11, and symmetricallytransforming the first reflective means 20 shown in FIG. 17 with respectto the bisecting line.

FIG. 19 shows another example in which no total internal reflection isperformed on the inner surface of an optical means 10.

As shown in this drawing, it can be seen that the augmented realityimage light output from an image output unit is directly transmitted toa first reflecting means 20 without total internal reflection throughthe interior of the optical means 10 and the augmented reality imagelight reflected by the first reflective means 20 is reflected by asecond reflective means 30, i.e., a plurality of reflective units 31 to35, and transmitted to the pupil 50.

Although the example shown in FIG. 19 is similar to the examples shownin FIGS. 15 and 17 , there are differences in the location of the imageoutput unit 40 and the location and angle of the first reflective means20.

FIG. 20 shows another case where total internal reflection is performedtwice on the inner surface of an optical means 10.

As shown in this drawing, it can be seen that the augmented realityimage light output from an image output unit is transferred to a firstreflective means 20 and the augmented reality image light reflected bythe first reflective means 20 is emitted toward the second surface 12 ofthe optical means 10, reflected by total internal reflection on thesecond surface 12, transferred to the first surface 11 of the opticalmeans 10, reflected by total internal reflection again on the firstsurface 11, transferred to a second reflective means 30, again reflectedby the second reflective means 30, and finally transferred to the pupil50.

It can be seen that the structure shown in FIG. 20 is substantially thesame as a structure obtained by, when the optical means 10 shown in FIG.19 is viewed toward a plane perpendicular to the z axis, trisecting theoptical means 10 shown in FIG. 19 along the x axis, setting onetrisecting line closer to the pupil 50 to the first surface 11, andsymmetrically transforming the first reflective means 20 shown in FIG.19 twice with respect to the trisecting line.

Although FIGS. 15 to 20 illustrate the structures in which totalinternal reflection is not performed inside the optical means 10 or isperformed one or more times inside the optical means 10, the presentinvention is not limited thereto.

It is obvious that various structures capable of transferring augmentedreality image light to the reflective means 20 through total internalreflection performed a different number of times may be possible.

Furthermore, it is obvious that the structures illustrated in FIGS. 15to 20 may also be applied to the first embodiment without change.

FIGS. 21 and 22 are diagrams showing the configuration of an opticaldevice 700 for augmented reality according to a modification of thesecond embodiment of the present invention, wherein FIG. 21 is aperspective view of the optical device 700 for augmented reality andFIG. 22 is a front view of the optical device 700 for augmented reality.

The optical device 700 for augmented reality shown in FIGS. 21 and 22has the same basic configuration as the optical device 600 for augmentedreality shown in FIGS. 13 and 14 , however, is characterized in that aplurality of second reflecting means 301 to 304 each including aplurality of reflective units 31 to 35 is provided.

In the optical device 700 for augmented reality, the plurality of secondreflective means 301 to 304 is arranged as below.

When an optical means 10 is placed in front of the pupil 50 of a userand the direction that extends forward from the pupil 50 is an x axis,an image output unit 40 is disposed outside or inside the optical means10 so that it is located on a straight line perpendicular to the x axis.Also, when any one of the line segments passing between the first andsecond surfaces 11 and 12 of the optical means 10 while being parallelto a vertical line from the image output unit 40 to the x axis along thex axis is a y axis and a line segment perpendicular to the x axis andthe y axis is a z axis, the plurality of second reflective means 301 to304 is arranged at intervals in parallel with each other along the zaxis direction.

Each of a plurality of reflective units 31 to 35 constituting each ofthe second reflective means 301 to 304 may be disposed to be locatedalongside any one of a plurality of reflective units 31 to 35constituting adjacent second reflective means 301 to 304, (i.e., secondreflective means 301 to 304 on both sides) along a virtual straight lineparallel to the z axis. In this case, when the plurality of secondreflective means 301 to 304 is viewed from the outside toward a planeperpendicular to the z axis, they appear the same as shown in FIG. 13 .

FIGS. 23 and 24 are diagrams showing the configuration of an opticaldevice 800 for augmented reality according to another modification ofthe second embodiment of the present invention, wherein FIG. 23 is aperspective view of the optical device 800 for augmented reality andFIG. 24 is a front view of the optical device 800 for augmented reality.

Although the optical device 800 for augmented reality according to theembodiment of FIGS. 23 and 24 is basically the same as the opticaldevice 700 for augmented reality described in conjunction with FIGS. 21and 22 , it is characterized in that at least some of a plurality ofreflective units 31 to 35 constituting each of a plurality of secondreflective means 301 to 304 are arranged not to be located alongside aplurality of reflective units 31 to 35 constituting adjacent secondreflective means 301 to 304 on a virtual straight line parallel to the zaxis.

In other words, as shown in FIGS. 23 and 24 , when the reflective units31 to 35 of the first reflective means 301 and the reflective units 31to 35 of the second reflective means 302, which are adjacent to eachother from the right direction of the z axis, are compared with eachother in sequence from an upper side (a side adjacent to an image outputunit 40) in the y-axis direction, it can be seen that each of thereflective units 31 to 35 of the first reflective means 301 is arrangednot to be located alongside any one of the reflective units 31 to 35 ofthe second reflective means 302 on a virtual straight line parallel tothe z axis.

In other words, the reflective units 31 to 35 of the first reflectivemeans 301 and the reflective units 31 to 35 of the second reflectivemeans 302 are not arranged alongside each other and are not aligned witheach other along a virtual straight line parallel to the z axis whenviewed in the z-axis direction.

FIGS. 25 and 26 are diagrams showing the configuration of an opticaldevice 900 for augmented reality according to still another modificationof the second embodiment of the present invention, wherein FIG. 25 is aperspective view of the optical device 900 for augmented reality andFIG. 26 is a front view of the optical device 900 for augmented reality.

Although the optical device 900 for augmented reality shown in FIGS. 25and 26 is basically the same as the embodiment described in conjunctionwith FIGS. 13 and 14 , it is characterized in that a plurality ofreflective units 31 to 35 is formed in bar shapes that extend alongvirtual straight lines parallel to a z axis.

In other words, as described above, when an optical means 10 is placedin front of the pupil 50 of a user and the direction that extendsforward from the pupil 50 is an x axis, an image output unit 40 isdisposed outside or inside the optical means 10 so that it can belocated on a straight line perpendicular to the x axis. Also, when anyone of the line segments passing between the first and second surfaces11 and 12 of the optical means 10 while being parallel to a verticalline from the image output unit 40 to the x axis along the x axis is a yaxis and a line segment perpendicular to the x axis and the y axis is az axis, the plurality of reflective units 31 to 35 is formed in barshapes that extend along virtual straight lines parallel to the z axis.

In the embodiments of FIGS. 13 to 26 , the first reflective means 20extends to become closer to the second reflective means 301 to 304 inthe directions from the center of the first reflective means 20 towardboth sides of the first reflective means 20 when is viewed in the x-axisdirection, and is thus formed in the shape of a moderate “U”-shaped baras a whole. Since this is the same as described in the first embodiment,a detailed description thereof is omitted.

Third Embodiment

FIG. 27 is a side view showing an optical device 1000 for augmentedreality according to a third embodiment of the present invention.

The embodiment shown in FIG. 27 is characterized in that a third surface13 through which the augmented reality image light output from an imageoutput unit 40 enters an optical means 10 is formed as a curved surfacehaving refractive power.

The third surface 13 through which the augmented reality image lightenters the optical means 10 is formed as a curved surface protrudingtoward the image output unit 40, and thus the third surface 13 functionsas a collimator for the augmented reality image light entering from theimage output unit 40.

Since the first reflective means 20 functions as a collimator embeddedin the optical means 10 as described above, the third surface 13 may beused as an auxiliary collimator, and thus the overall collimationperformance in the optical device 1000 for augmented reality may beimproved.

Although the third surface 13 is illustrated as being formed between thefirst surface 11 and the second surface 12 in FIG. 27 , the presentinvention is not limited thereto. It should be noted that the thirdsurface 13 refers to a surface through which the augmented reality imagelight output from the image output unit 40 enters the optical means 40.

Meanwhile, in FIG. 27 , the third surface 13 formed as a protrudingcurved surface is applied to the second embodiment, this may also beapplied to the first embodiment.

FIG. 28 is a side view showing an optical device 1100 for augmentedreality according to a modification of the third embodiment of thepresent invention.

Although the embodiment shown in FIG. 28 is basically the same as theembodiment shown in FIG. 27 , it is characterized in that an auxiliaryoptical means 70 is disposed between an image output unit 40 and a thirdsurface 13.

Although the auxiliary optical means 70 is formed as a convex lens inFIG. 28 , this is illustrative. A combination of at least one or more ofother various reflective means, refractive means, and diffractive meansmay be used as the auxiliary optical means 70. The overall performanceof the optical device 1100 for augmented reality may be improved byappropriately utilizing such an auxiliary optical means 70.

The auxiliary optical means 70 shown in FIG. 28 may also be applied toboth the first and second embodiments.

Fourth Embodiment

FIGS. 29 to 31 are diagrams showing an optical device 1200 for augmentedreality according to a fourth embodiment of the present invention,wherein FIG. 29 is a front view showing the optical device 1200 foraugmented reality when viewed from the pupil 50, FIG. 30 is a side viewshowing the optical device 1200 for augmented reality when viewed towarda plane perpendicular to an z axis, and FIG. 31 is a plan view showingthe optical device 1200 for augmented reality when viewed toward a planeperpendicular to an y axis.

Although the optical device 1200 for augmented reality shown in FIGS. 29to 31 includes a plurality of second reflective means 301 to 305 in thesame manner as the optical device 700 for augmented reality shown inFIGS. 13 and 14 , they are different in that there is at least onesecond reflective means 301, 302, 303, 304 or 305 that is disposed suchthat the distance between the second reflective means 301 to 305 and thesecond surface 12 of the optical means 10 is different from thedistances between the other second reflecting means 301, 302, 303, 304and/or 305 and the second surface 12 of the optical means 10.

In other words, as described above, when the optical device 1200 foraugmented reality is placed in front of the pupil 50 of a user and thedirection that extends forward from the pupil 50 is an x axis, any oneof the line segments passing between the first and second surfaces 11and 12 of an optical means 10 while being parallel to a vertical linefrom an image output unit 40 to the x axis along the x axis is a y axis,and a line segment perpendicular to the x axis and the y axis is a zaxis, the second reflective means 301 to 305 are arranged such thatthere is at least one second reflective means 301, 302, 303, 304 or 305that is disposed such that the distance between the second reflectivemeans 301, 302, 303, 304 or 305 and the second surface 12 of the opticalmeans 10 is different from the distances between the other secondreflecting means 301, 302, 303, 304 and/or 305 and the second surface 12of the optical means 10.

In other words, as shown in FIG. 30 , it means that at least some of theplurality of second reflecting means 301 to 305 are disposed such thatnot all of them appear to be superimposed on each other when is viewedtoward a plane perpendicular to the z-axis.

In the embodiment of FIGS. 29 to 31 , the second reflective means 301 to305 are arranged such that the distance between the two secondreflective means 301 and 305 shown by dotted lines and the secondsurface 12 of the optical means 10, the distance between the two secondreflective means 302 and 304 shown in black and the second surface 12 ofthe optical means 10, and the distance between the one second reflectivemeans 303 and the first surface 12 of the optical means 10 shown inwhite are different from one another.

In this case, although the distances between the two second reflectivemeans 301 and 305 shown by dotted lines and the second surface 12 of theoptical means 10 are shown as being the same and the distances betweenthe two second reflective means 302 and 304 shown in black and thesecond surface 12 of the optical means 10 are shown as being the same,this is illustrative. It is obvious that the distances between thesecond reflective means 301 to 305 and the second surface 12 of theoptical means 10 may be all different from one another.

The embodiment shown in FIGS. 29 to 31 may also be applied to the first,second and third embodiments.

According to the present invention, there is provided the compactoptical device for augmented reality, which is capable of significantlyreducing the size, thickness, weight, and volume thereof, effectivelyblocking a ghost image, and providing a wide field of view.

Furthermore, according to the present invention, there is provided thecompact optical device for augmented reality, which is capable ofminimizing the leakage of image light of the real world, which maygenerate a ghost image, to the pupil of a user, thereby maximizing asee-through property and also providing a clear virtual image, and isalso capable of utilizing a structure in which a plurality of reflectiveunits configured to transfer augmented reality image light to the pupilby reflecting it toward the pupil is arranged, thereby providing a widefield of view and also improving the optical efficiency at whichaugmented reality image light is transferred to an eye box.

Although the present invention has been described with reference to thepreferred embodiments of the present invention, it is obvious that thepresent invention is not limited to the above-described embodiments andother various modifications and alterations may be possible.

What is claimed is:
 1. A compact optical device for augmented realityhaving a ghost image blocking function and a wide field of view, thecompact optical device comprising: an optical means configured totransmit at least part of real object image light therethrough toward apupil of an eye of a user; a first reflective means disposed inside theoptical means, and configured to transfer augmented reality image lightwhich is image light corresponding to an image for augmented realityoutput from an image output unit to a second reflective means; and asecond reflective means disposed inside the optical means, andconfigured to reflect the augmented reality image light transferred fromthe first reflective means and transfer the augmented reality imagelight to the pupil of the eye of the user, thereby providing an imagefor augmented reality to the user; wherein the optical means has a firstsurface which the real object image light enters, and a second surfacethrough which the augmented reality image light transferred via thesecond reflective means and the real object image light are outputtoward the pupil of the eye of the user; wherein the augmented realityimage light output from the image output unit is transferred to thefirst reflective means through inner part of the optical means, or isreflected by total internal reflection on at least any one of innersurfaces of the optical means and transferred to the first reflectivemeans; wherein a reflective surface of the first reflective means whichreflects the augmented reality image light is disposed to face the firstsurface of the optical means which the real object image light enters;wherein the second reflective means includes a plurality of reflectiveunits disposed inside the optical means to transfer the augmentedreality image light, transferred from the first reflective means, to thepupil of the user by reflecting the augmented reality image light; andwherein the plurality of reflective units constituting the secondreflective means is arranged inside the optical means such that each ofthe plurality of reflective units is located closer to the secondsurface of the optical means as a distance from the first reflectivemeans to the reflective unit increases.
 2. The compact optical device ofclaim 1, wherein the first reflective means is disposed inside theoptical means in opposite to the image output unit with the secondreflective means interposed therebetween.
 3. The compact optical deviceof claim 1, wherein the reflective surface of the first reflective meansis formed as a curved surface.
 4. The compact optical device of claim 3,wherein the reflective surface of the first reflective means is formedto be concave toward the first surface of the optical means.
 5. Thecompact optical device of claim 1, wherein the first reflective meanshas a length less than 4 mm in a widthwise direction thereof.
 6. Thecompact optical device of claim 1, wherein a surface opposite to thereflective surface of the first reflective means is coated with amaterial that absorbs light without reflecting light.
 7. The compactoptical device of claim 1, wherein the plurality of reflective unitsconstituting the second reflective means is disposed to have an inclinedangle with respect to the second surface of the optical means in orderto transfer the augmented reality image light, transferred from thefirst reflective means, to the pupil by reflecting the augmented realityimage light toward the pupil.
 8. The compact optical device of claim 1,wherein each of the plurality of reflective units has a size smallerthan 4 mm.
 9. The compact optical device of claim 8, wherein the size ofeach of the plurality of reflective units is a maximum length betweenany two points on an edge boundary of the reflective unit.
 10. Thecompact optical device of claim 8, wherein the size of each of theplurality of reflective units is a maximum length between any two pointson an edge boundary of an orthographic projection obtained by projectingthe reflective unit onto a plane including a center of the pupil whilebeing perpendicular to a straight line between the pupil of the user andthe reflective unit.
 11. The compact optical device of claim 1, whereineach of the plurality of reflective units is disposed such that theaugmented reality image light transmitted from the first reflectivemeans is not blocked by remaining other reflective units.
 12. Thecompact optical device of claim 1, wherein sizes of the plurality ofreflective parts are partially different from each other.
 13. Thecompact optical device of claim 1, wherein an interval between at leastsome of the plurality of reflective units is different from an intervalbetween remaining other reflective units.
 14. The compact optical deviceof claim 1, wherein a surface, being opposite to a surface that reflectsthe augmented reality image light, of at least some of the plurality ofreflective units is coated with a material that absorbs light withoutreflecting light.
 15. The compact optical device of claim 1, whereinsurfaces of at least some of the plurality of reflective units areformed as curved surfaces.
 16. The compact optical device of claim 1,wherein an inclined angle of at least some of the plurality ofreflective units with respect to the optical means is formed to bedifferent from that of remaining other reflective units.
 17. The compactoptical device of claim 1, wherein: the second reflective means includesa plurality of reflective means; when the optical means is placed infront of the pupil of the user and a direction that extends forward fromthe pupil is an x axis, the image output unit is disposed outside orinside the optical means so that it is located on a straight lineperpendicular to the x axis; and when any one of line segments passingbetween the first and second surfaces of the optical means while beingparallel to a vertical line from the image output unit to the x axisalong the x axis is a y axis and a line segment perpendicular to the xaxis and the y axis is a z axis, the plurality of second reflectivemeans is arranged at intervals in parallel with each other along an zaxis direction.
 18. The compact optical device of claim 17, wherein eachof a plurality of reflective units constituting each of the plurality ofsecond reflective means is disposed to be located alongside any one of aplurality of reflective units constituting adjacent second reflectivemeans along a virtual straight line parallel to the z axis.
 19. Thecompact optical device of claim 17, wherein at least some of a pluralityof reflective units constituting each of the plurality of secondreflective means are disposed not to be located alongside any one of aplurality of reflective units constituting adjacent second reflectivemeans on a virtual straight line parallel to the z axis.
 20. The compactoptical device of claim 1, wherein: when the optical means is placed infront of the pupil of the user and a direction that extends forward fromthe pupil is an x axis, the image output unit is disposed outside orinside the optical means so that it is located on a straight lineperpendicular to the x axis; and when any one of line segments passingbetween the first and second surfaces of the optical means while beingparallel to a vertical line from the image output unit to the x axisalong the x axis is a y axis and a line segment perpendicular to the xaxis and the y axis is a z axis, the plurality of reflective units isformed in bar shapes that extend along virtual straight lines parallelto the z axis.
 21. The compact optical device of claim 17, wherein thefirst reflective means extends to become closer to the second reflectiveunit in directions from a center of the first reflective means towardboth sides of the first reflective means when viewed in the x axis. 22.The compact optical device of claim 1, wherein a third surface throughwhich the augmented reality image light output from the image outputunit enters the optical means is formed as a curved surface havingrefractive power.
 23. The compact optical device of claim 1, wherein:the second reflective means includes a plurality of reflective means;and when the optical device is placed in front of the pupil of the user,a direction that extends forward from the pupil is an x axis, any one ofline segments passing between the first and second surfaces of theoptical means while being parallel to a vertical line from the imageoutput unit to the x axis along the x axis is a y axis, and a linesegment perpendicular to the x axis and the y axis is a z axis, there isat least one of the second reflective means that is disposed such thatdistances between the second reflecting means and the second surface ofthe optical means are not the same as each other.
 24. The compactoptical device of claim 18, wherein the first reflective means extendsto become closer to the second reflective unit in directions from acenter of the first reflective means toward both sides of the firstreflective means when viewed in the x axis.
 25. The compact opticaldevice of claim 19, wherein the first reflective means extends to becomecloser to the second reflective unit in directions from a center of thefirst reflective means toward both sides of the first reflective meanswhen viewed in the x axis.
 26. The compact optical device of claim 20,wherein the first reflective means extends to become closer to thesecond reflective unit in directions from a center of the firstreflective means toward both sides of the first reflective means whenviewed in the x axis.